Signal lamp unit



March 10, 1936. s/M. DovR SIGNAL LAMP UNIT Filed Feb.v 4, 1955 I V E NTOR.

ATTORNEY. Y

atented Mar. 1o, 1936 UNITED STATES PATENT OFFICE "Miyt N i This invention relates to signal lights, and\ more particularly such lights as are mounted on the outside of automobile trucks or the like,

l and is especially concerned with a multiple light 5 unit which shall be simple and `economical of construction and possess other advantages hereafter set forth.

Automobile trucks are generally provided with a rear signal light unit comprising a channelshaped frame having a plurality of spaced lights thereon, generally three, for purposes well known in the art. Such light units project out-` wardly from the truck and are relatively unprotected against injury byropes or the like that may be used for securing the load. The greater the thickness of the unit thefurther it projects outwardly of the truck and the greater is the probability of injury to the unit.

In the prior constructions of signal light units of the type here concerned, a plurality of electric bulbs with their individually associated reflector and/or cover glass holding means are located entirely on the outer side of the web of a chanvnel-shaped strip, the electric conductor for the. 25 lamps being located on the other side of the web, that is, in the trough of 'thechanneL The circuit to the contact in the base of each bulb is madefby a terminal that is spring-pressed against the contact ofthe bulb. In those prior constructions, the terminal and the spring means for vmaintaining the pressure of the terminal against the bulb contact are located entirely on the outer side of the web of the channel, that is, on the same side that the entire lamp is located. As a result, the total height or thickness of the unit is considerable. It is an object lof the 'presentwinvention to provide a lighting unit of the above general class which shall be. oi! a minimum thickness, thus reducing,- as far 4Q. as possible, the probability of injury to the unit in normal use. I have found` that by changing the construction of the terminal which engages the contact in the base of the electric bulb there is ample available space in the trough of the channel-shaped frame to allow for the mounting of that terminal on the inner side of the web of the channel frame. My construction also permits the electric vbulb to be so mounted that a portion of the base thereof extends through the web of the channel, so that only a portion of the entire bulb extends in frontof the web, and none of the terminal structure is in front of the web of the channel. By this construction the overall thichiess of the unit is considerably reduced.

It is a further object of the present invention to simplify the spring-pressed terminal structure use on lighting units off the above general class. The terminal of my unit comprises a narrow strip of conducting metal lying on top 5 of a wider. strip of stiff but flexible insu1ation.` 'Ihe terminal strip extends the full length of the strip of insulation, centrally thereof, and is riveted thereto at its opposite ends. At each point where the terminal vstrip is engaged by a bulb 10 contact it has a shallow cupped depression formed therein. The strip of insulation is of a width sufilcient to iit snugly between the flanges of the channel frame, and it is located between those ilanges, with the terminal strip side thereof facing thevweb of the channel. Each flange of the channel has a plurality of projections punched therein for holding the strip of insulation in place. 'I'he holding or supporting profjections are spaced apart sufficiently to permit an appreciable ilexing or outward bowing of the strip between adjacent Asupporting projections upon the application of proper force to accomplish that result. The supportinglprojectionsl are so spaced that no projection is located immediately opposite a lamp-receiving opening or lsocket in the web of the channel. When the -a' i-lrm spring pressure is maintained between he terminal and the bulb contact, without the ual springs that. are generally used. ,By this arrangement not only is the size of the unit 40 reduced. but also the cost, for I have eliminated the terminal assemblies heretofore used, as well as the springsfor pressing the respective terminals against the contacts, of the light bulbs. The cost of the structure f added. is approximately equal to, or even less than, the cost of the labor previously required` for wiring the unit,

which wiring work present unit.

It is a still further object of the present invention to simplify the holding means for the light bulbs by eliminating the usual tubular sockets heretofore provided for that purpose.

has been eliminated in the The sockets in the present invention comprise merely openings in the web of the channel frame, 5 5

each opening having two short diametrcally opposed slots for receiving the pins that project from the stern of the light bulb. After the end of a bulb has been inserted into the opening, and turned 90 degrees, it is held against upward movement, and the spring pressure of the terminal strip and its backing holds the bulb rmly in position.

The attainment of the above and further objects of the present invention will be apparent from the following specification, taken in conjunction with the accompanying drawing forming a part thereof. In the drawing:

Figure l is a side View of a lighting unit constructed in accordance with the present invention, certain of the parts being broken away to illustrate the construction;

Figure 2 is a sectional View taken along the line 2-2 of Figure 1;

Figure 3 is a perspective view of the terminal unit;

Figure 4 is a fragmentary view of the under side of the web of the channel at one of the light bulb sockets; and

Figure 5 is an end view of the unit.

Referring now more particularly to the drawing, in Figure 1, I have shown a multiplelight unit having three lights thereon. The unit comprises a sheet metal channel-shaped support I on which the various parts are assembled. The channel includes flanges 2 2 and a web portion 3, the ends of which are bent over, as indicated at 4, to form extensions 5 for mounting the unit, as is usual in the art. Instead of the extensions 5, the flanges 2-2 may be provided with short laterally-projecting mounting iianges at their lower end, since the frame I may be mounted in place in any desired manner. Three holes, forming light bulb sockets, are formed in the web of the channel, one of the holes being indicated at 6. At each of the sockets is secured a disc-like shallow saucer-shaped lamp housing and cover lens holder 1, which is adapted to hold any preferred type of lens 1 in the usual manner. The members 1 aresecured to the web of the channel I in any preferred manner, in this instance by forming a very slight tubular projection around the hole 6, which projection fits into a hole in the member 1 and is then beaded over, as indicated at 8 in Figure 2. It is, however, to be understood that any other method of securing the two may be used insofar as concerns the broad aspects of the present invention.

The holes 6 are of a diameter just sufficient to permit the stem of a proper electric light bulb to be inserted therethrough. The base of such bulbs has two diametrically opposite pins projecting therefrom, for holding the bulb in a bayonet type socket. To permit the bulb base, with its projecting pins, to pass through the hole 6, there are formed, in the metal at the edge of the hole 6, two short pin-receiving slots Ill-I0. After the base of a bulb is inserted into the socket the bulb-s turned 90 degrees, whereupon the pins in the bulb base come opposite a pair of diametrically spaced short indentations II-II on the under side of the web 3 at the edge of the opening 6, for holding the bulb against turning.

Each of the flanges 2-2 has a number of very short inwardly punched indentations I5 formed thereon. These indentations serve as a support for a terminal unit to be presently described. It is suiiicient here to state that none I the indentations is located directly opposite a light bulb socket, for reasons which will be apparent as this description proceeds.

The terminal unit of the present invention is ilustrated in Figure 3. It comprises a. strip I1 of stiff but flexible and resilient insulating material, to which is secured a narrow contact strip of metal I8 of good electric conductivity, by rivets I9 and 20. One suitable material is the substance known as Formica, which comprises thin sheets of paper impregnated with the substance known as bakelite" and treated by heat and pressure to form one piece of material. The rivet I9 serves also to secure an insulated com ductor 2| in firm electric engagement with the contact strip. The contact strip I8 has a number of terminals 22 formed thereon and suitably spaced so that a terminal is opposite each socket 6 when the terminal unit is asembled in the channel frame. Each terminal 22 is formed by merely stamping the contact strip with a suitable die to produce a projection, the upper surface 0f which forms a bulb contact receiving cavity. The strip I1 is of a length only slightly less than the distance between the ends 4-4 of the channel-shaped support I, and of a width slightly less than the inside width of the channel of the frame.

When the terminal unit is inserted in place it lies flat in the channel of the frame I, resting upon the indentations I5. When a bulb is inserted into its socket, the tip contact in the base of the bulb engages the corresponding terminal 22 and forces it downwardly, thus flexing the strip I1 as illustrated in Figure 1. The strip I1, being rather stii, exerts a considerable spring pressure against the contact at the lower end of the bulb base, thus maintaining a firm electric engagement between the bulb contact and the terminal 22. Also, the spring pressure between the contact and the terminal 22 prevents any rattling or shifting lof the strip I1 in the channel of the frame due to vibration or sudden movements of the vehicle on which the unit is mounted, and, by maintaining an upward force on the bulb, the pins of the bulb are held in the indentations II-II, thus holding the bulb against turning.

It is to be noted that the members 1 are exceedingly shallow and lie quite close to the web of the channel. This reduces, quite appreciably, the possibility of loose ropes, or the like, being caught under one of said members and then pulling the member of! as the ropes are drawn taut. Also, it is to be noted that the bulb extends outwardly of the web of the channel by an amount appreciably less than the full length of the bulb including its base, since an appreciable portion of the base of the bulb is below the web of the channel-shaped support I. Thus the entire overall thickness ofI the unit is very much less than that of corresponding units heretofore available. Also, it is to be noted that I have omitted the usual pressure contact maintaining springs that maintain a pressure engagement with the contact in the base of the bulb, and I have also eliminated the usual cylindrical socket-forming member heretofore provided for receiving the bulb base. All this has tended towards simplification of the unit from the point of view of cost, as well as reduced the overall thickness of the same.

The indentations, or projections, I are spaced from the sockets so as to permit flexing of the strip I1. At the ends of the unit one of the ini* v l 2,033,692

dentations I must necessarily be quite close to the bulb: socket. Therefore thel indentation on the other side of the end Vsocket is spaced somewhat further from the bulb socket, thus again permitting appreciable llexing of the strip I1.

The circuit through each bulb is by way of conductor 2i, strip I8 and a terminal 22, to the contact on the l'base of the light bulb, thence V-shaped trame having a'plurality of electric bulb sockets iormed inl-fthe web thereof, and within tlietrough oi the Achannel a terminal assembly comprising a comparatively long and narrow strip oi iierible insulation, means lor supporting 'thectrlp of insulation in the channel, a contact stripertending longitudinally oi the insulating strip along the center ci onetsurface ci the insulating strip, said contact strip having aV plurality oi dished contacting terminals formed as an integral part oi the contact strip and spaced from one another lengthwise of the contact strip, said terminals being opposite the reE spectlve bulb sockets.

2. A multiple light unit comprising a channelshaped trame having a plurality of electric bulb sockets termed in the web thereof, and within the trough oi* the channel a terminal assembly comprising a comparatively long and narrow strip oil idenible insulation; a contact strip entending longitudinally oi the insulating strip along one siu'iace of the insulating strip, said contact strip being opposite the respective lamp sockets, and means for supporting the terminal assembly in the trough oi the channel comprising a plurality ci spaced indentations formed in the ilanges oi the channel and upon which the insulating strip rests.

t. il multiple signal light unit adapted to be mounted on the outside ot a vehicle, said unit comprising a channel-shaped trame having means lor mountingr the same, said trame having spaced holes formed in the web thereof and constituting bulb sockets, electric bulbs in the respective sockets with the bases or the bulbs extending into the trough ol the channel, and

-thei comprising electric bulb sockets, a terminal assembly within the trough of the channeL said assembly comprising a strip ol insulation ol stid hexible material with a conductor strip along the center thereof, said strip of insulation lying substantially parallel to the plane of the 'web of the channel andv spaced therefrom, means for supporting said insulating strip comprising indentations formed in the flanges of the channel and on which the insulating strip rests, .the insulating strip being free of xed support at the respective bulb sockets, thereby permitting flexing o1' the insulating strip at the lamp sockets, said conductor strip being engaged by the contact on the base of a bulb when a bulb is inserted into a socket, and exerting a pressure on the bulb contact. y Y

5. A multiple light unit comprising a channelshaped frame having holes formed in the web thereof comprising electric bulb receiving sockets, a terminal assembly within the trough of the channel, said assembly comprising a strip of! insulation of stiu" ilegible material with a conductor strip .along one face thereof, said strip oi insulation lying substantially parallel to the plane or. the -web of the channel and spaced therefrom, and means for supporting said insulating strip.

6. .d multiple light unit comprising a channelshaped trame having holes formed in the web thereoi comprising electric bulb receiving sockets, the material at the edge of each hole having pinreceiving slots formed therein, a vterminal as sembly within the trough of the channel, said assembly comprising a strip ci insulation or stiti horrible material with aconductor strip along the center thereof, said conductor strip having bulb contact receiving terminals at points opposite the bulb sockets, said strip of insulation lying substantially parallel to the plane oi theweb or the channel and spaced therefrom,

means for supporting said insulating strip coina bulb is insertedinto a socket, whereby the strip i oi insulation is eiied away from the web by a bulb inserted into the socket and thus exerts a spring pressure on the bulb to maintain the terminal in pressure engagement with the con= tact at the base oi the bulb.

7. .il multiple light unit comprising achannelshaped trame having holes formed in the web thereof vfor receiving electric light bulbs, a unitary horrible terminal, assembly on the inner side oi the web of the channel comprising a contract strip and a supporting strip or insulation PAboth extending lengthwise of the channel, inA

alignment with the holes and spaced from the web oi the channel to permit engagement oi the contact strip by a bulb inserted in any of the holes, and means tor supporting the terminal assembly adjacent each hole thereby prevent ing recession of the contact strip out of engagement with a bulb in one hole when the contact strip is flexed away from the web of the channel by a bulb in an adjacent hole.

8. A light unit comprising a channel-shaped trame having a plurality of holes formed in the web thereof, means at each hole forming va. bayonet type electric bulb socket, and within the trough of the channel a terminal assembly including a exible contact strip extending lengthwise of the channel opposite the holesy and spaced from the web of the channel an amount less than the amount that a bulb projects through the holes, whereby a bulb deects the strip from its normal position, and means supporting the terminal assembly in the trough of the channel .and permitting flexing of the terminal assembly away from the`web of the channelby the pressure of a lamp bulb inserted into a hole, said supporting means being spaced alongr the length of the channel so that the pressure of the contact against any bulb is substantially independent of the amount of deflection of the strip produced by any other bulb.

9; A multiple signal light unit adapted to be mounted on the outside of a vehicle, said unit comprising a channel-shaped frame having spaced holes formed in the web thereof and constituting electric bulb sockets, electric bulbs in the respective sockets with'the bases of the bulbs extending into the trough of the channel,

.and means extending'within the trough of the ing holes therein constituting bulb sockets, a I

contact strip extending longitudinally of the plate structure in alignment with the sockets and spaced from the plate structure and insulated therefrom, bulbs in the sockets and engaging the contact strip, and means supporting the' contact strip and maintaining a spring pressure engagement between the contact strip and the bulb, said means including a flexible strip of insulation extending lengthwise of the structure and supporting the contact strip and including also means at each socket for supporting the flexible strip while permitting flexing of the same away from the plate structure at the respective sockets.

11. A multiple light unit comprising a channel-shaped frame having holes formed in the web thereof for receiving electric bulbs, electric bulbs in the respective holes with the bases of the bulbs extending through the web of the channel into the trough thereof, a contact strip Within the trough of the channel and extending lengthwise thereof and engaging the tips of the bulbs, and resilient insulating means also extending the length of the channel and pressing the contact strip against the bulbs, said resilient insulating means being supported at a plurality of places along the length of the channel, whereby it may be flexed away from any hole byl a bulb therein while maintaining a substantially constant pressure against the other bulbs.

12. A terminal assembly comprising a comparatively long and narrow strip of flexible insulation, a contact strip extending longitudinally of the insulating strip along the center of one surface of the insulating strip, said contact strip having a plurality of dished contacting terminals formed as an integral part of the contact strip and spaced from one another lengthwise of the contact strip. a

SAMUEL M. DOVER. 

